SK 101

The pressurized shaft kiln works strictly counter-currently, allowing for excellent heat transfer and the adjustment of defined process conditions. This kiln allows a very wide range of operational temperatures and defined temperature profiles necessary for the production of high density, high grade MgO sinter.

The feed passes at a constant speed through the kiln with a constant controlled flow of air passing through the bed from the bottom to the top. Therefore, the cold air cools the burned product from burning temperature of 1900°C - 2000°C to a discharge temperature of 100°C - 200°C. At the same time, the air is preheated to above 800°C and at that point, fuel is blown into the kiln together with a controlled and measured amount of air.

Under these conditions, the fuel reacts spontaneously, generating extremely high temperatures. Consequently, the gas volume expands drastically, resulting in high gas velocities leading again to an extremely effective, uniform and controlled heat transfer. When the burning temperature is reached, the sintering process begins.

In order to control the required burning temperature and to avoid overheating, cold air is introduced together with the fuel. By balancing this fuel and air ratio, an exact control of the peak temperature and the temperature profile are maintained.

The shaft kiln consists of a cylindrical steel shell made of special steel. This cylinder is lined with special refractories (high grade alumina castable in the bottom section, high grade MgO bricks with magnesite ramming for the rest). The lining is 700 mm thick and the active length is 10 meters.

A discharge mechanism consists of a rotating table resting on a massive bearing block. The discharge table rotates at a very low speed which is adjustable by means of a frequency controlled motor. A constant and continuous flow of burned sinter is maintained.